Snap switch with movable contacts on biased rocking plate



Aug. 22, 1967 KIYOSHI YAMADA 3,337,703

SNAP SWITCH WITH MOVABLE CONTACTS ON BIASED ROCKING PLATE Filed Aug. 25, 1966 3 sheetsfisheet 1.

JNVENTOR. Kwosm YAMADA I W f. 7 MM, A'rrvs Aug. 22, 1967 KIYosI-II YAMADA 3,337,703 SNAP SWITCH WITH MOVABLE cou'mc'rs 0N BIASED ROCKI-NG PLATE Filed Aug. 25, 1966 5 Sheets-Sheet 3 I ENDING POINT, ENGAGING TIM 1 OFF JNVEN TOR. KIYosI-II YAMADA M44, 'IWWJGM United States Patent 3,337,703 I SNAP SWITCH WITH MOVABLE CONTACTS ON BIASED ROCKING PLATE Kiyoshi Yamada, Kadoma-shi, Osaka, Japan, assignor to Matsushita Denko Kabushiki Kaisha, Osaka, Japan, a corporation of Japan Filed Aug. 25, 1966, Ser. No. 575,008 Claims priority, application Japan, Aug. 30, 1965, 40/ 71,539 4 Claims. (Cl. 200--67) ABSTRACT OF THE DISCLOSURE An electric snap switch having a rocking plate provided with movable contact points at both ends is supported with a fulcrum plate of a common terminal and a slider provided at an end of a handle is made to slide on the upper surface of said rocking plate so that the movable contacts will alternately contact with and separate from fixed contacts, said rocking plate being provided with a leaf spring thereunder in such manner that longitudinal directions of the rocking plate and the leaf spring will always correspond with each other, and said rocking plate being always pushed up with said leaf spring in a state that both being made to always electrically contact with each other.

This invention relates to switches to be used mostly for or the like.

In a conventional snap switch, as illustrated in FIG. 4, a rocking plate C provided with movable contacts A and B at both ends is supported with a fulcrum plate E of a common terminal D and a slider G of a handle F is made to slide on the upper surface of said rocking plate C so that the movable contacts A and B may alternately contact with and separate from fixed contacts H and I, respectively. In such conventional mechanism, in case the slider G slides rightward from the state shown in FIG. 4, the slider will so quickly incline under its resiliency that the left end of the rocking plate C will bounce with the impact force and a vibration will be caused between said rocking plate C and fulcrum plate E. As the fulcrum plate E and rocking plate C are charging parts, chattering (Which is a phenomenon for the charging parts to repeatedly contact with and separate from each other) will be caused between them. Thus there is a defect that the fulcrum plate E and rocking plate C will be damaged by heat in such case.

In the conventional snap switch, the larger the amount of the accumulated energy required to push down the handle, the larger the impact and vibration at the time of switching. The bouncing phenomenon will be large not only in the contact part but also in any dynamically unstable part.

Generally, if the switching speed is increased, the energy at the time of engaging the contact will be so large that the bouncing time after the engagement will be longer. This is a very important problem specifically in switching an electric power. The chattering at the time of switching and the bouncing at the time of closing will fuse and wear the contacts, will increase the contact resistance with the increase of the concentrated resistance by arcs and will generate noises. These unbalanced states are caused by the switching speed, opening and closing time and contact pressure. Even if the physical amount governing the chattering phenomenon is clarified, it will not be easy to apply it to the mechanism. The present inventor has investigated a vibration caused by a collision between two rigid bodies. As a result, it has been made improvements of snap communication machines auxiliary spring for damping the vibration with the,

mechanism without directly controlling the vibration generated at the time of the operation of main switching elements.

A principal object of the present invention is to provide a snap switch wherein the bouncing of a rocking plate and the generation of a vibration between the rocking plate and the fulcrum are prevented so that the generation of chattering and the damage of the contacts by heat may be prevented.

Another object of the present invention is to provide a snap switch wherein the opening and closing operation can be carried out positively over a long period.

FIG. 1 is a vertically sectioned view of a snap switch embodying the present invention.

FIGS. 2 and 3 are vertically sectioned views of other snap switches embodying the present .invention.

FIG. 4 is a vertically sectioned view of a conventional snap switch.

FIG. 5 shows operation characteristics of the snap switch of the present invention.

FIG. 6 shows operation characteristics of the conventional snap switch.

Embodiments of the present invention shall now be explained with reference to the drawings.

In FIG. 1, 1 is a rocking plate provided with movable contacts 2 and 3 at both ends and 4 is a fulcrum plate sup porting said rocking plate 1 and riveted and fixed to the bottom of a case 12 together with a common terminal 5. 6 is a leaf spring located below the rocking plate 1, secured in the middle to the fulcrum plate 4 with a rivet 13 and in contact at both ends 6a with the lower surface of the rocking plate 1 so as to always push up the rocking plate 1. 7 is a handle set in a tubular metal fixture 15 fixed to an upper cover 14 and rotatably held with a shaft 16 secured at both ends to the metal fixture 15. 8 is a slider inserted through a spring in a deep hole 9 made in the handle 7 so as to be resiliently pressed on the upper surface of the rocking plate 1. 10 and 11 are fixed contacts to alternately contact with and separate from the movable contacts 2 and 3, respectively, and riveted to the bottom of the case 12 together with terminals 17 and 18, respectively.

FIG. 2 shows another embodiment of the present invention. Its difference from the one shown in FIG. 1 is that the leaf spring 6 is fixed at one end 6a to one end of the rocking plate 1 with the contact 3 and is mounted at the other end 6a on the fulcrum plate 4.

FIG. 3 shows another embodiment of the present invention wherein the leaf spring 6 is fixed at both ends 6a to both ends of the rocking plate 1 with the contacts 2 and 3 and a projection 1a projecting downward is made in the middle of the rocking plate 1 so as to curve the leaf spring 6 downward in the middle. Further, the lower surface of said leaf spring 6 is supported with either of both side walls 4a and 4b of the fulcrum plate 4.

The operation of the snap switch of the present invention shall now be described. Now, as shown in FIG. 1, the slider 8 is inclined leftward. If the slider 8 is inclined rightward from this state, an impact force will be generated on the rocking plate 1 by the quick inclination of the slider 8. But, as said rocking plate 1 is always pushed up with the leaf spring 6, said leaf spring 6 will become a cushion to reduce the impact force.

Therefore, the rocking plate 1 will not bounce as in the conventional switch and no vibration will be caused between said rocking plate 1 and fulcrum plate 4. Thus there are effects that chattering caused by such vibration can be prevented, the damage of the contacts by heat can be eliminated and the opening and closing operation of the switch can be made positively over a long time.

The bounce of the rocking plate will roughen the contact surfaces until the contacts are covered with electrically insulative films and become poor in conduction or fuse. FIGS. and 6 show examples of the bounce of the rocking plate when engaged. FIG. 5 is of a snap switch of the present invention. FIG. 6 is of a conventional snap switch. It is seen in these diagrams that, in the snap switch of the present invention, the bounce of the rocking plate is so much less than in the conventional one as to be substantially no trouble in practice. The present invention is not limited to these embodiments but can be variously modified within the spirit of the claims.

What is claimed is:

1. An electrical snap switch comprising the combination of an electrical terminal and an electrically conductive fulcrum member connected to said terminal, an electrically conductive rocking plate pivotally supported on said fulcrum plate so as to provide an electrical connection therewith and carrying a pair of contact elements at opposite ends of the plate, a pair of stationary contact elements mounted for contact with said contact elements on the opposite ends of said rocking plate upon tilting movement of said rocking plate on said fulcrum member, an actuating handle tiltably mounted above said rocking plate and carrying a sliding control element on the lower end thereof, said control element being spring biased against said rocking plate to urge the conductive rocking plate against said conductive fulcrum member, and an electrical-1y conductive auxiliary leaf spring connected between said conductive fulcrum member and said conductive rocking plate, said leaf spring engaging said rocking plate at a point spaced laterally away from its fulcrum point and biased against said rocking plate toward said sliding control element with a biasing force smaller than the biasing force on said' sliding control element whereby a continuous electrical connection is maintained between said fulcrum member and said rocking plate.

2. An electrical snap switch as defined in claim 1 wherein said auxiliary leaf spring is fixed at its center to said fulcrum member by means of said electrical terminal so as to form two laterally projecting arms engaging the underside of opposite end portions of said rocking plate and biased thereagainst.

3. An electrical snap switch as defined in claim 1 wherein said auxiliary leaf spring is fixed at one end to one end of said rocking plate by means of one of said contact elements, the other end of said spring engaging said electrical terminal and biased thereagainst.

4. An electrical snap switch as defined in claim 1 wherein the opposite ends of said leaf spring are fixed to opposite ends of said rocking plate, said fulcrum member forms a pair of laterally spaced vertical walls, and the central portion of said leaf spring projects downwardly between said vertical walls so that said fulcrum member is in continuous supporting engagement with a portion of said rocking plate on at least one side of said downward projection.

References Cited UNITED STATES PATENTS 2,248,361 7/1941 Krieger 200-677 2,274,917 3/1942 Carlson et al 20068 2,606,259 8/1952 Huetten 200166 ROBERT K. SCHAEFER, Primary Examiner.

D. SMITH, JR., Assistant Examiner. 

1. AN ELECTRICAL SNAP SWITCH COMPRISING THE COMBINATION OF AN ELECTRICAL TERMINAL AND AN ELECTRICALLY CONDUCTIVE FULCRUM MEMBER CONNECTED TO SAID TERMINAL, AN ELECTRICALLY CONDUCTIVE ROCKING PLATE PIVOTALLY SUPPORTED ON SAID FULCRUM PLATE SO AS TO PROVIDE AN ELECTRICAL CONNECTION THEREWITH AND CARRYING A PAIR OF CONTACT ELEMENTS AT OPPOSITE ENDS OF THE PLATE, A PAIR OF STATIONARY CONTACT ELEMENTS MOUNTED FOR CONTACT WITH SAID CONTACT ELEMENTS ON THE OPPOSITE ENDS OF SAID ROCKING PLATE UPON TILTING MOVEMENT OF SAID ROCKING PLATE ON SAID FULCRUM MEMBER, AN ACTUATING HANDLE TILTABLY MOUNTED ABOVE SAID ROCKING PLATE AND CARRYING A SLIDING CONTROL ELEMENT ON THE LOWER END THEREOF, SAID CONTROL ELEMENT BEING SPRING BIASED AGAINST SAID ROCKING PLATE TO URGE THE CONDUCTIVE ROCKING PLATE AGAINST SAID CONDUCTIVE FULCRUM MEMBER, AND AN ELECTRICALLY CONDUCTIVE AUXILIARY LEAF SPRING CONNECTED BETWEEN SAID CONDUCTIVE FULCRUM MEMBER AND SAID CONDUCTIVE ROCKING PLATE, SAID LEAF SPRING ENGAGING SAID ROCKING PLATE AT A POINT SPACED LATERALLY AWAY FROM ITS FULCRUM POINT AND BIASED AGAINST SAID ROCKING PLATE TOWARD SAID SLIDING CONTROL ELEMENT WITH A BIASING FORCE SMALLER THAN THE BIASING FORCE ON SAID SLIDING CONTROL ELEMENT WHEREBY A CONTINUOUS ELECTRICAL CONNECTION IS MAINTAINED BETWEEN SAID FULCRUM MEMBER AND SAID ROCKING PLATE. 